Tool Converts Thoughts of Paralysed Patients into Action

The University of Chicago has presented the first published results from initial participants in a clinical trial of their interface system, a "neuromotor prosthesis".

The first patient was Matthew Nagle, a 25-year-old Massachusetts man with a severe spinal cord injury. After having the sensor implanted on the surface of his brain at Rhode Island Hospital, he learned to control a computer cursor simply by thinking about moving it. Nagle learned to open simulated e-mail, draw circular shapes using a paint program on the computer and play a simple video game using only his thoughts. He could change the channel and adjust the volume on a television, even while conversing. He was ultimately able to open and close the fingers of a prosthetic hand and use a robotic limb to grasp and move objects.

"The results," said John Donoghue, professor and director of the brain science program at Brown University, "hold promise to one day be able to activate limb muscles with these brain signals, effectively restoring brain-to-muscle control via a physical nervous system."

The system consists of a 4x4 millimetre sensor, with 100 tiny electrodes, each thinner than a human hair. The sensor is implanted on the surface of the area of the brain responsible for voluntary movement, the motor cortex. The electrodes penetrate into the surface of the brain where they pick up electrical signals from nearby neurons and transmit them through thin gold wires to a titanium pedestal that protrudes about an inch above the patient's scalp. A cable connects the pedestal to computers, signal processors and monitors.

However, the scientists say that the current system is still in its infancy and is far from perfect. It is bulky and cumbersome. The quality of the signal can vary from patient to patient and from day to day. A great deal of work remains to be done to extend the longevity and reliability of the sensor.; Source: University of Chicago